Conventional solar panels using passive solar tracking systems employ a frame pivotable about an axis. The systems typically have two canisters at opposing ends that are connected to each other via a conduit. The canisters are filled with a volatile fluid that transfers between canisters based on the temperature in each of the canisters. More specifically, once solar energy heats one of the canisters at a temperature greater than the other canister, the volatile fluid will pass to the other canister and cause passive rotation of the solar panel.
U.S. Pat. No. 4,476,854 illustrates a passive solar tracking system as described above that has solar panels mounted on a pipe. The panels rotate about an axis defined by a rod. Canisters are positioned at opposing ends of a frame. A conduit connects the canisters to facilitate transfer of a volatile fluid between the canisters as the canisters are heated to different temperatures. The passive solar tracking system further includes a bracket that may be manually adjusted to improve solar input on the panels. However, since the bracket requires manual adjustment, such a tracking system does not provide bi-directional tracking of a solar panel or group of panels. Moreover, the design of the tracking system makes it vulnerable to wind damage since the pipe provides support for the frame and solar panels.
U.S. Pat. No. 4,198,954 provides an alternative solar tracking system that has a reflector pivotable about a horizontal axis. Tubular reservoirs are connected via a conduit and act as sun sensors. A rod and bellows moves a lever, which pivots the reflector upon heating of the tubular reservoirs. The reflector further includes tubular reservoirs that are connected via a conduit. The heating of the tubular reservoirs causes rotation of the reflector. More specifically, a rotary disc is positioned on the base plate. The rotary disc includes a gearwheel and transmission, which is connected to a lever, to rotate the reflector about a vertical axis. Certain disadvantages are associated with this conventional solar tracking system. Specifically, debris may accumulate between the rotary disc and base plate preventing rotation of the rotary disc.
An example of a bi-directional solar tracking is provided by U.S. Publication No. 2011/0048406. This solar tracking system has scissor shaped structures or lifters that facilitate pivoting of the solar panel about two perpendicular axes. Certain disadvantages are associated with this known solar tracking system. Specifically, the configuration of the lifters is complicated and susceptible to damage from twisting and torsional movement of the solar panel under wind conditions.
Therefore, a need exists for a solar tracking system and methods for passively collecting solar energy that is resistant to environmental factors such as wind, rain, and debris, and otherwise minimizes damage to the solar panel for bi-directional passive tracking. The present invention satisfies this demand.